The former chief reporter on Britain's News of the World tabloid has defended a story alleging David Beckham had an affair because the footballer and his wife had projected a fairy-tale marriage to the public in order to sell products.

Neville Thurlbeck said the rise of privacy lawsuits in Britain over the past three years had all but killed the kiss-and-tell tales that used to be a staple of tabloid front pages.

Thurlbeck said there had been a public interest in the story about the star's alleged affair with his personal assistant Rebecca Loos in 2004 while promoting a picture of a stable marriage to singer and fashion designer Victoria.

Beckham at the time denied the allegation.

"What we saw happening outside of the marriage was in direct contrast to the image they were cultivating," Thurlbeck told Britain's Leveson Inquiry, which was set up to investigate press standards in response to a phone-hacking scandal at the tabloid.

"We said they were making millions of pounds on the back of that wholesome image and we thought it very important at the time to expose that," he said.

Thurlbeck said the News of the World, shut down by Murdoch as the phone-hacking scandal escalated in July, had paid a six-figure sum to Loos.

"It was the most, I think, I've ever paid for a story," he said.

"Privacy has become a huge matter over the last three years. I would say the kiss-and-tell story is largely dead as a genre."

Thurlbeck is thought to be the intended recipient of a key piece of evidence in the phone-hacking probe, the so-called "For Neville" email containing transcripts of hacked conversations that appear to show hacking went beyond a lone "rogue reporter".

The email is at the centre of allegations that News Corp executive James Murdoch knew earlier than he has claimed that the illegal practice was more widespread, as other senior former managers claim to have made him aware of it in 2008.

Thurlbeck, who was arrested in April in connection with the phone-hacking affair, did not answer specific questions on Monday that might prejudice his criminal case.